[pct-l] Ankles

Mon Feb 28 18:25:28 CST 2011

Boots keep my ankles warm. They are cold in my running shoes. Especially in
the snow.

I'll be hiking the PCT in runners.

Have a great day everyone! :)

On Sun, Feb 27, 2011 at 5:00 PM, Yoshihiro Murakami <
completewalker at gmail.com> wrote:

> Thanks,  greg
>
> It seems to be the same old dispute. People tend to think within their
> experience. But, personal experience do not always disclose the truth.
>
> I have found three good scientific papers.  Of course, there are many
> wrong scientific papers, so we need to be careful to evaluate their
> results.
>
>
> -----This paper indicated that the ankle fixation do not increase
> energy expenditure. Experimental research ( single group )
>
>
> Gait Posture. 2008 Oct;28(3):427-33. Epub 2008 Mar 24.
> Ankle fixation need not increase the energetic cost of human walking.
> Vanderpool MT, Collins SH, Kuo AD.
> Department of Biomedical Engineering, University of Michigan, Ann
> Arbor, MI 48109-2125, USA.
> Abstract
> We tested whether the metabolic energy cost of walking with the ankles
> immobilized can be comparable to normal walking. Immobilization of any
> lower extremity joint usually causes greater energy expenditure.
> Fixation of the ankle might be expected to eliminate the work it
> normally performs, to detrimental effect. But fixation using
> lightweight boots with curved rocker bottoms can also bring some
> benefits, so that the overall energetic effect might be quite small.
> We measured oxygen consumption, kinematics, and ground reaction forces
> in six (N=6) able-bodied human volunteers walking at 1.25 m/s in three
> conditions: normal walking in street shoes, walking with ankles
> immobilized by walking boots, and normally with ankles free but also
> weighted to match the mass of the walking boots. We estimated
> metabolic energy expenditure, joint work, and overall work performed
> on the body center of mass as a function of ankle fixation. Ankle
> fixation with walking boots caused the total rate of energy
> expenditure for walking to increase by 4.1% compared to normal
> (P=0.003), but differed by an insignificant amount (0.4% less, P=0.78)
> compared to walking with equivalent ankle weight. Compared to normal
> walking, ankle fixation can reduce ankle torque and work during the
> stance phase, most notably during late stance. This apparently makes
> up for the loss of ability to push-off as normal. With a suitably
> lightweight apparatus and curved rocker bottom surface, loss of ankle
> motion need not increase energy expenditure for walking.
>
>
> -----This paper disclosed that the  high-top shoes deduced the
> Achilles tendon loading. This paper adopted good experimental design
> (matched pare comparison trial),  so the conclusion of this study may
> be  trustful.
>
>
> Clin J Sport Med. 2010 Sep;20(5):344-9.
>
> Can footwear affect achilles tendon loading?
> Rowson S, McNally C, Duma SM.
> Center for Injury Biomechanics, Virginia Tech-Wake Forest University,
> Blacksburg, VA, USA. srowson at vt.edu
>
> Abstract
> OBJECTIVE: To investigate the effects of footwear on Achilles tendon
> tension by directly measuring Achilles tendon tension and dorsiflexion
> range of motion.
> DESIGN: A total of 48 matched pair tests were performed comparing the
> effects of shoe type (high-top vs low-top) for each shoelace
> configuration (tied vs untied). These were performed using the
> Achilles tendons of 4 human cadaver lower extremities that were
> instrumented with a customized load cell designed to measure tension.
> The lower extremity was inverted in a custom testing apparatus
> designed to inertially invoke dorsiflexion of the foot, putting the
> Achilles tendon in tension.
> SETTING: Research laboratory.
> PATIENTS: Left and right lower extremities of 2 human cadavers.
> INTERVENTIONS: None. Independent variables were shoe type and shoelace
> configuration.
> MAIN OUTCOME MEASURES: Achilles tendon tension and dorsiflexion range of
> motion.
> RESULTS: High-top shoes significantly reduced peak Achilles tendon
> tension by an average of 9.9% when compared with low-top shoes. Tied
> laces significantly reduced peak tension for low-top (3.7%) and
> high-top (12.8%) shoes when compared with untied laces. With tied
> laces, high-top shoes significantly reduced peak dorsiflexion angle by
> an average of 7.2% when compared with low-top shoes. Tied laces with
> high-top shoes significantly reduced peak dorsiflexion angle by an
> average of 4.7% when compared with untied laces. A P value of 0.05 was
> determined to be significant.
> CONCLUSIONS: This study offers valuable insight that footwear can
> affect Achilles tendon loading during dorsiflexion.
>
>
>
> ------ When we wear boots, the joint loading at the knee might be
> increased.
>
>
>
> J Biomech. 2010 Sep 17;43(13):2467-72. Epub 2010 Jun 11.
> Effect of boot shaft stiffness on stability joint energy and muscular
> co-contraction during walking on uneven surface.
> Böhm H, Hösl M.
>
> Gait Laboratory, Orthopedic Hospital for Children, Bernauerstr. 18,
> Aschau i. Chiemgau, Germany. boehm at mytum.de
>
> Abstract
> Increased boot shaft stiffness may have a noticeable impact on the
> range of motion of the ankle joint. Therefore, the ability of the
> ankle joint to generate power for propulsion might be impaired. This
> might result in compensatory changes at the knee and hip joint.
> Besides, adaptability of the subtalar joint to uneven surface might be
> reduced, which could in turn affect stability. The aim of the study
> was therefore to investigate the influence of boot shaft stiffness on
> biomechanical gait parameters. Fifteen healthy young adults walked
> over coarse gravel wearing two different hiking boots that differed by
> 50% in passive shaft stiffness. Leg kinematics, kinetics and
> electromyography were measured. Gait velocity and indicators for
> stability were not different when walking with the hard and soft boot
> shaft over the gravel surface. However, the hard boot shaft decreased
> the ankle range of motion as well as the eccentric energy absorbed at
> the ankle joint. As a consequence, compensatory changes at the knee
> joint were observed. Co-contraction was increased, and greater
> eccentric energy was absorbed. Therefore, the efficiency of gait with
> hard boots might be decreased and joint loading at the knee might be
> increased, which might cause early fatigue of knee muscles during
> walking or hiking. The results of this study suggest that stiffness
> and blocking of joint motion at the ankle should not be equated with
> safety. A trade-off between lateral stiffness and free natural motion
> of the ankle joint complex might be preferable.
>
>
>
>
>
>
>
>
>
>
> 2011/2/28 greg mushial <gmushial at gmdr.com>:
> >> Message: 1
> >> Date: Sat, 26 Feb 2011 21:22:15 -0800
> >> From: Eric Lee <saintgimp at hotmail.com>
> >> Subject: Re: [pct-l] Ankles
> >> To: "'CHUCK CHELIN'" <steeleye at wildblue.net>, "'PCT listserve'"
> >> <pct-l at backcountry.net>
> >> Message-ID: <BAY145-ds58A75378F235D5E51F142BDDF0 at phx.gbl>
> >> Content-Type: text/plain; charset="us-ascii"
> >>
> >> Steel-Eye wrote:
> >>>
> >> Diane is correct in her assessment that typical hiking boots contribute
> >> little, or nothing, to resist ankle-turning.  The low style boots are
> >> about
> >> 6" in height.  Medium heights are maybe 8" high.  Neither is much higher
> >> than the distance from the ground to the center of the ankle joint and
> >> they
> >> won't contribute significantly to absorbing torque about the ankle
> >> regardless of how tightly they are laced.  They may feel nice and snug
> and
> >> firm - a physiological advantage - but they will not significantly
> resist
> >> even a mild turn, let alone a 2g - 3g turn possible with a misstep on
> the
> >> trail.
> >>>
> >
> > Eric - I believe there is an additional factor which has gone
> unmentioned:
> > that is the leverarm effect. The force exerted against one's ankle in the
> > rolling under process, is applied via a leverarm, namely that part of the
> > foot below the ankle. This leverarm effect is offset by the width of the
> > foot, ie, a broad base resisting any  rolling laterally. It seems as the
> > boots get heavier, the thickness of the soles increases, or more
> > importantly, that leverarm distance, from the ground to the ankle is
> > increased...  making it easier to twist an ankle, or said differently,
> > making it more difficult for the connective tissue of the ankle to resist
> > being turned under. This is way I've gone with two types of walking
> shoes:
> > one with micro thin soles, which do not contribute to this leverarm
> length;
> > and boots with incredibly stiff sides (typically mountineering boots),
> which
> > because of the increased leverarm length, would be more inclined to twist
> > ankles, but because of the stiffness, that tendency is more than offset.
> In
> > my book, the worst ankle twisters are the boots with very thick soles
> (ie,
> > lengthened leverarm distance), but with thin soft almost glove leather
> > (offering no additional resistance to rolling under)...  in my book
> they're
> > an accident waiting to happen. I've noticed this same effect in running
> > shoes with exaggerated soles - equally deadly.
> > TheDuck
> >
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>
>
>
> --
> Sincerely
> --------------- --------------------------------------
> Hiro    ( Yoshihiro Murakami )
> Blogs http://completewalker.blogspot.com/
> Photo http://picasaweb.google.co.jp/CompleteWalker/
> Backpacking since about 1980 in Japan
> 2009 JMT, the first America.
> 2010 JMT, the second America.
> ------------------------------------------------------
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